Shell Eco-Marathon

Overview

The Shell Eco-marathon is an energy optimization competition between student organizations all around the world. In accordance with the Shell Eco-marathon competition, the team’s goal is to increase the fuel efficiency of the car. Specifically, the team focused on light weighting and making improvements to the fuel, brakes, wheels, steering, and electronics systems.

Objectives

A general objective was to decrease weight wherever possible within the vehicle. The past team also requested for the elimination of fuel leaks, procurement of a master cylinder that fully compresses the brake calipers, replacement of the disintegrated wheel hubs, installation of the new low rolling friction Michelin tires, removal of unnecessary material from the steering system, and the elimination of brake engagement when starting the car.

Approach

– Customer needs were determined through the club suggestions document and a meeting with the sponsor.
– The team was then divided into three sub teams to accommodate the first three focus systems: fuel, wheels, and brakes.
– For the fuel system, research was conducted into the procurement of a fuel quick connector, clear hoses, and a smaller pressure vessel. The parts were then integrated, and pressure tested to ensure no leakage. Also, more effective mounts for the fuel flow sensor and bottle were designed and manufactured.
– For the brakes system, research was conducted into the procurement of a more efficient master cylinder. After integration, the brake lines were also rewired, and leak tested. Furthermore, the brake discs and brake pedal were replaced with their lighter counterparts.
– For the wheels system, research was conducted into procurement of Onyx hubs and rims for the new Michelin tires. With the Onyx hubs’ dimensions differing from the old hubs, the non-driven shafts were redesigned and a sleeve for the driven shaft was designed.
– The workload for the fuel and brakes systems was dwindling, which prompted the team to improve upon the steering and electronics systems.
– For the steering system, the steering wheel, push quick connector, and the rack were machined to remove unnecessary material. The mount was completely redesigned and replaced with a 3D print.
– For the electronics system, a button was wired that tricks the engine into thinking the brake is compressed.

Outcomes

– The risk of fuel leaks has been drastically decreased, detection of air bubbles has been enabled, pressurization of the system is much faster, and the mounts allow for more efficient installation of the fuel flow sensor and bottle.
– The master cylinder can push approximately fifty percent more fluid volume. The system was also made lighter with the substitution of lighter brake discs and parking brake.
– The new Onyx hubs were connected to the old wheel system and new axles were made to accommodate the size difference. There was research done to get new rims for the Micheline tires given to the team but the process of finding the correct one is being handed to the next team with research on which rims to buy and test.
– The steering weight decreased from 1441.8 grams to 990.5 grams.
– The need to engage the brakes when starting the car was eliminated, which better accommodates the strategy of burn and coast.